Skin-Colored Nodules on the Knuckles —Quiz Case

Multinucleate cell angiohistiocytoma: a case report and review of the literature.

“…Multinucleate cell angiohistiocytoma shows a predilection for middle-aged to elderly women (female to male ratio 3:1) [7], with the majority of cases diagnosed in the 5th to 8th decade [2,4,8]. Clinically, MCAH manifests as single or multiple, firm, reddish-brown to violaceous dome-shaped papules with a smooth surface [2,7,9]. Lesions are usually sharply demarcated and distributed in a random, linear, or annular pattern [2,3,7].…”

“…Lesions are usually sharply demarcated and distributed in a random, linear, or annular pattern [2,3,7]. They appear most often over the extremities, including the distal thighs, calves, and dorsal aspect of the hands [4,7,9]. Although rare, there have been 4 reported cases of generalized MCAH [5,8].…”

“…Although rare, there have been 4 reported cases of generalized MCAH [5,8]. In most cases, the lesions are asymptomatic, but pruritus may be present [6,9]. Spontaneous regression has been observed in a few cases, but lesions tend to persist with slow progression [2,6,7].…”

“…Spontaneous regression has been observed in a few cases, but lesions tend to persist with slow progression [2,6,7]. Clinical differential diagnosis includes Kaposi's sarcoma, acroangiodermatitis (pseudo-Kaposi sarcoma), granuloma annulare, lichen planus, and sarcoidosis [3,7,9]. Biopsy and histopathologic examination are essential to diagnosing MCAH.…”

“…The surrounding dermis consists of haphazardly arranged collagen bundles and mononuclear cells with a fibrohistiocytic appearance [3,7]. A sparse perivascular and perifollicular infiltrate of lymphocytes, histiocytes, and occasional neutrophils and plasma cells may also be seen [7,8,9]. Few extravasated red blood cells may be present, but hemosiderin deposition is rarely observed [3,8].…”